Hmm, I'm not a lady, but I'll answer this anyway.
I've seen a couple of gay guys in a Victoria's Secret when I went with my ex-gf once. They had plucked eyebrows, looked much better than the average man, and wore jeans I thought would only fit on a girl. How did I know they were gay? When I was leaving the mall later that day I saw them making out behind the dumpster.
I don't remember them saying anything to anyone about how good certain bras would look though, as far as i knew they were just regular cashiers.